Heat gas or charcoal grill.
Combine cheese, chicken and salsa.
Divide the cheese mixture evenly over 4 tortillas. Top with remaining tortillas; press lightly.
Grill tortillas uncovered on medium heat 4 to 6 minutes, turning once, until cheese begins to melt and tortillas begin to brown. Watch carefully!
Cut each quesadilla into quarters and serve with sour cream and salsa for dipping, if desired.
