After months of not posting, it's probably already obvious that I abandoned this hack (for personal reasons I won't bore you with). I took a ton of notes before I had to quit, though, and I still hear occasional murmurs online of people wanting to hack AW for In Nomine, so I figured I'd post some of what I ended up with here in case someone stumbles upon it and feels like using it themselves later.
PLAYBOOKS, CHOIRS/BANDS & SUPERIORS
I never settled on how to handle playbooks, but I fiddled with two approaches. I have a ton of notes on this (including fully written out playbooks for individual Choirs and Superiors), but this post is going to be long enough as it is; message me directly if you actually ever want details.
Approach #1: Separate playbook for Choir/Band and Superior. Players pick two playbooks at character creation to combine them. The advantage is that it allowed for more text, allowing you to translate the resonances more directly from the original setting. The disadvantage was that it was cumbersome to have two playbooks.
Approach #2: Each playbook represented one Superior's Word from In Nomine. Every playbook had every Choir's resonance, dissonance, and Choir attunement listed on it. Rather than trying to translate resonances directly, I basically just made resonances into expansions of the basic moves. (Seraph resonance: "When you read someone and ask whether they're telling the truth," you get extra info, and know The Truth on a 12+. Balseraph resonance: "When you manipulate someone into believing your version of the truth," etc.) It meant more text on your playbook that didn't ever actually apply to you, but fewer playbooks for you to fumble with in total (and it's never bad to have a reminder of what your buddies can do).
STATS, BASIC MOVES & PERIPHERAL MOVES
I went with the standard Apocalypse World stats, albeit slightly renamed (Hard, Cool, Sharp, Smooth, Strange). I was never entirely happy with my altered basic moves, but here are some peripheral moves that might be helpful to anyone trying to hack In Nomine themselves.
Wake from Trauma: When you attempt to wake from trauma, roll+cool. On a 10+, you wake up feeling pretty with it. On a 7-9, you wake up feeling pretty disoriented; take -1 forward. On a miss, you stay in trauma. You can't attempt this move until you've been in trauma for a few days (say, 1 per decade that you've been on Earth duty), and you can only try the move daily. Change those to "weeks" and "weekly" in Limbo.
Listen to the Symphony: When you listen to the music of the Symphony, roll+strange. (Gain an additional +1 for a loud disturbance, +2 for a deafening disturbance.) On a 10+, you can sense echoes of disturbances and get a general idea of what caused them, plus a strong sense of where and when they happened. On a 7-9, you just get a vague sense of where and when. On a miss, you can still vaguely sense if something happened, but you definitely look like the weirdo who walks down the street listening for outer space transmissions.
Identify an Artifact: When you spot something you suspect is an artifact, roll+strange. On a 10+, you recognize it as an artifact, and have an idea of its general function. On a 7-9, you recognize it as an artifact, but damned if you know what it does.
Assume Another Form: When you wish to shed your vessel and to switch to another vessel or assume celestial form, roll+strange. On a 10+, you do it and cause a loud disturbance. On a 7-9, you do it, but must either exhaust your essence or cause a deafening disturbance instead of a loud one. ["Exhausting essence" was kind of like the "reload" tag on AW weapons, but more confusing than it needed to be.]
Suffer Dissonance: When you do something against your celestial nature, add 1 to your dissonance countdown and roll+dissonance. On a 7-9, take -1 forward. On a 10+, take -1 forward and choose 1:
• Go Outcast or Fall. (Not an option for Malakim or demons.)
• Gain 1 discord of the GM's choice (if you have any left to gain).
When your dissonance countdown reaches 12:00, if you're an angel, you Fall, then erase all dissonance. If you're a demon, every time you suffer dissonance, you gain 1 discord (even if it means coming up with new ones) and you suffer all the effects of the above list.
Convert Dissonance to Discord: Anytime you're not in the middle of suffering dissonance, you may convert dissonance to discord. If your dissonance countdown is at 9:00 or below, you may erase all dissonance and gain 1 discord. If your dissonance counter is above 9:00, you may exchange dissonance for discord on a 1 for 1 basis until you get down to 9:00.
Invoke a Superior: When you attempt to invoke your Superior, roll+favor. (+1 for highly favored, +0 for favored, -1 for unfavored, and -4 for a Superior you don't serve.) On a 10+, your Superior arrives and you lose favor. On a 7-9, your superior knows you tried to get in touch, but has better things to do. On a miss, either your Superior doesn't bother to show up, or your Superior shows up and decides servitors who need too much handholding must be taught a lesson.
Accept Redemption: If you are a demon being granted redemption from an Archangel, roll+dissonance. On a 10+, you become an angel of the opposing Choir, losing all your old dissonance, attunements, and rites. On a 7-9, you also lose some memories, or lose -2 to your old resonance stat but gain +1 to your new resonance stat. On a failure, you don't make it.
IN NOMINE ATTUNEMENTS
I went through and turned every Choir and Servitor attunement into the game into a move. Some make the transition more easily than others. Here are a few examples, but feel free to message me if you feel like seeing more.
Dominic's "Vassal of Judgment" distinction: When you stare down a mundane NPC or a PC with cool 0 or less, they immediately confess their crimes.
Kyriotate of Trade: When you resonate to possess a host, treat a 6- roll as a 7-9 roll.
Ofanite of War: At the start of a fight, you may choose to make a move before any opponent gets to act.
IN NOMINE SKILLS AS MOVES
Rather than porting over the entire In Nomine skill list (which is sort of a strangely slapdash collection of skills of varying levels of utility), I made some extremely general "skill moves" that PCs could elect to take at character creation or when they take an advancement. You could technically pick any skill when you advance, but I meant for them to be matched up with particular superiors (e.g., technical skills listed on the Lightning playbook). Here are a few examples.
Technical skills: When you fiddle with one kind of mundane technology (pick one, like cars, personal computers, security systems, or _____________), roll+sharp. On a 10+, you do as much as you can with whatever tools and time you've got. On a 7-9, the GM also picks one:
• Your sloppy work causes a ruckus or leaves it noticeably fiddled with.
• It takes way longer than expected.
• You need to get or do something else before you can finish.
On a miss, the GM could pick all three, but you probably broke the damn thing beyond repair.
Fighting: When you use your preferred weapon or fighting technique (pick one, like firearms, swords, wrestling, or _____________), you can choose to do +1 or -1 harm on a successful hit.
Driving: When you pull off stunts behind the wheel, roll+cool. On a 10+, choose 3; on a 7-9, choose 2:
• You cause little damage.
• You (or your passengers, or your ride) suffer little damage.
• You make good time and/or outrun any pursuers.
SO, YEAH
That's enough of that. Feel free to message me if you're working on an AW/IN hack and want to talk shop. I had fun working on this and would be happy to help out someone looking to do it their own way.
EDIT to add: Oh yeah, the reason these moves are all using 2d6 numerical ranges rather than 3d6 (as my original post suggested) is that I changed my mind on that part way through. Someone on a forum suggested that if you want to keep In Nomine's "111" and "666" rolls, just have a custom move: "When you roll a 1-1 or a 6-6, roll another d6. On a 1-1-1, it's a divine intervention; on a 6-6-6, it's a demonic intervention." Never got to playtest it, but I like the idea, at least.