Depends what kind of indoors you mean, as in what kind of floor surface.
My method isn't the safest, maybe not even the most effective. But shit it's fun!
My Grandmothers house always had a heap of their mud nests up under her eaves when we'd visit.
Boys being boys we had slingshots so we would always be potting the nests with marbles.
Damn good for target practice!
I've found the best way to do it is fill a 600ml plastic bottle with petrol then put the bottle over the hole and let it drain out. The bottle keeps the entry blocked until the match it lit, then BOOM!