Yeah, I kinda doubt AAA alkalines are up to running a couple of servos, especially if they are high performance servos. A glitch buster/stutter stopper should help, but may not be enough. Cheap enough to try though.

Safest option is a NiMH receiver pack. To run Lipo (unregulated anyway) need to confirm your servos and the receiver can handle the higher voltage. What model servos? A LiFe pack is an in between option. I suspect available space will drive the actual pack selection, I’m guessing there is not much room to work with on a nitro 1/12 scale.