Cook meat with seasoning mix as directed on package.
Remove from heat; stir in 1/2 cup sour cream.
Spread beans down centers of tortillas; top with meat mixture and 1/2 cup cheese. Fold in opposite sides of each tortilla, then roll up, burrito style.
Place, seam-sides down, in 13x9-inch baking dish sprayed with cooking spray; cover.
Bake 25 min. Top with remaining cheese; bake, uncovered, 5 min. or until melted.