Small Arms, ManPack SRM/LRMs, Explosives, MREs, Water Purifiers, Mini Fusion Chargers, and Batteries. Battlemechs, Suitcase Nukes, Chem/Bio Weapons, will just bring down whomever you are fighting down on you like a ton of Bricks. You will trade a Garrison for a regiment, brigade, division, and they are going to practice hunting you.
Battlemechs cannot effectively fight an insurrection without War Crimes and Wanton Civilian Damage. Now you may be able to play that against the occupiers for a while with the populace, however once you kill or get killed enough locals that support will evaporate.
No one will be marching a Company of Mechs against the Star League and winning, and short of a DCMS/Clan Trials, 3SW battles, or way out in the Periphery, no one else will be marching a company Mechs anywhere and winning either.
So stock it with standard insurgency gear that has been effective for 1000 years.