Layer summer squash pieces in 9x13 pan. Dot with butter. Bake at 375 degrees for about 30 minutes or until squash are tender.
While squash is cooking, brown meat in a skillet over medium heat. When cooked through, add Taco or Mexican seasoning.
To assemble nachos, place cooked squash slices on a plate. Cover with taco meat, cheese and fresh salsa.