Strategy
1. need to isolate Magnaguard to prevent his taunt
2. fracture GG
3. spread your damage around the other droids and charge up nihilus Annihilate.
4. if fracture expires before GG can be annihilated, swap TM around and Stun GG to get fracture back ASAP
5. Do NOT remove GGs protection, he will force taunt some other droid
6. once annihilate is ready, destroy GG, and after that its just cleanup on the other droids
7. side droids can be killed while GG is fractured, but its not recommended as it gives you less time to allow thrawn to re-fracture
8. high speeds and tankiness is helpful to survive B1 attacks and get annihilate off quickly