Flash:Staff. Make him come to you and poke him hard.
Batman:Staff/Escrima For this matchup I use the staff 60% of the time but don't be like me unless you want a jumping kicking Batman 24/7
Cyborg:Staff/Escrima. Escrima for getting in and Staff when you're right next to him.
Green Arrow:Staff
Superman:Staff/Escrima. You gotta utilize between the two or you'll get bodied
Raven: I use staff all the time since she can just laugh at your escrima all day with her far ass grab. DB2 staff is what I mostly use for this match to punish her grabs and her teleporting B.S
Aquaman:Staff ALLLLLLLLL THE WAYYYYY. There's no reason for you to use escrima in this matchup.
Wonder Woman: Haven't fought alot of WW but I mostly use staff cause I'm comfortable with it in this matchup
Hawkgirl: I use staff so that I can punish her trait with flying grayson when she's about to fly. When I'm under her while she does her flying mace thing I just use J2 and then combo. This matchup is not easy though whether you're using escrima or staff.
Shazam: Staff is easier for this matchup
Green Lantern: Staff/Escrima
Joker: Staff
Harley Quinn: Staff
Solomon Grundy: Staff/Escrima. In my personal experience both are good against Grundy since both have really good zoning tools although Escrima has better zoning tools for this matchup. Reason being if you do DB2 MB in staff he'll do MB swamp hands and that grants him armor and trap you after you do your ground pound. This lets Grundy to move in on you. I just use MB wing dings all day for this matchup since he has no way to trap you with swamp hands while you're in the air and if he try to do those armor grabs simply MB wing dings to get past his super armor and sent him far back to the other side of the screen.
Lex Luthor: Not enough MU experience with him. 2000 games in and I have not seen ONE lex luthor. Is he that bad? Anyway I would use staff for this MU since he's big and I like to use staff on big characters.
Catwoman: Escrima for me. Wing dings/Ground Spark to zone her out if you can and then get in on her. I tried using staff most of the time when I use ground pound I get punished for a combo(I forgot what that move is called when catwomen can just dash full screen without getting hurt). Your staff pokes won't do much against her, especially if she's crouching. MB staff spin won't work on a crouching catwoman and so is standing 1.
Deathstroke: Staff(if you ever run into a zoning DS, this is the stance you should stick with).
Ares:Staff all the way. Ground pound beats most of his moves. Even after he threw a projectile if you groundpound it will interrupt the projectile. Ground pound punish alot of his moves and even if he try to get close to you he doesn't have much options close range.
Killer Frost: Escrima I think. I just avoid being on the ground due to her ice slide and use wing dings.
Doomsday: Staff. If he try to supernova you just do MB B3 for punish since Nightwing doesn't have a very good dash in this stance. I also manage to poke Doomsday alot in this stance whenever he get close to me. D1 and DB3 is good tools against his trait.
Sinestro: Staff. About to throw rocks? Flying grayson. About to draw balls at your face? Ground pound. About to get in on you? Poke him hard
Black Adam: Escrima. Stay in the air at all times unless you want to eat food dive/lightning all day long.
Bane: Staff(or escrima). Both are good for this MU in my opinion but Bane shouldn't be a problem for NW users.
Lobo: Lol(staff/escrima. Just zone him)
Batgirl: Staff. Her dive bomb can easily punish most of NW moves. Don't let her get close to your or it's high/low time
When in doubt, use staff.