If "few" means 2, yes. But no more than that. Many tomatillo plants get huge, bigger than tomato plants.

Personally I'd only plant one per container of that size and group 2 or 3 of them - in separate containers - near each other for better pollination, production, and better control of the nutrients and watering needs.

Dave

Probably 15 gallon tub has more than enough soil for two but Tillos get very bushy and wide. You may try to plant them one at each end and when they start getting tangled, just prune them.