In a large skillet, heat butter until hot. Add eggs; cook and stir over medium heat until eggs are completely set. Remove from the heat; stir in the cheese, tomato and picante sauce.
Spray one side of a tortilla with cooking spray. Place tortilla greased side down on a griddle. Spoon half the egg mixture on half of the tortilla.
Fold over and cook over low heat for 1-2 minutes on each side or until cheese is melted and tortilla is golden brown. Repeat with remaining tortilla and egg mixture. Cut into wedges and serve with sour cream and additional picante sauce.