I love my Milwaukee fuel! The batteries really do hold up well in the cold, I still keep my spare in a cooler/insulated bag with hand warmer. For a 6” nils an older model fuel drill (725lb torque) will be more than enough. Just make sure it’s brushless. The newest models are coming out with 1200lb torque, and upwards of 9ah batteries, you won’t need that much lol. I got my 7” lazer auger, drill, and clam plate back in 2015 with 725lb torque. still running with the original two 4ah batteries. With 20” of ice, I got worn out drilling before I use up both batteries when I tried. Mind you, I was making a grid pattern to actually cover water to fish from, not just drilling hole after hole to count... and usually loose count lol.
Oh and there’s an adapter that can be found for the nils to clam plate. Even if there isn’t an issue with nils catching on the bottom of the ice, having the plate really stabilizes the whole rig and allows more control.