Thaw tofu, 8 hours to overnight. Place in a colander with a weight on top to squeeze moisture out.
Place tofu on a flat work surface and cut into approximately 16 'nuggets.'
Mix milk, mustard, garlic salt, onion powder, and pepper together in a bowl. Pour break crumbs into a separate bowl. Dip each nugget into the milk mixture and roll into the bread crumbs, coating completely.
Heat oil in a skillet over medium-high heat. Add nuggets; cook, flipping halfway, until golden brown, about 7 minutes.