1. Combine Velveeta and Rotel in 1 1/2 quart microwaveable bowl; microwave on high 3 minutes or until velveeta is completely melted and mixture is well blended, stirring after 2 minutes.
2. Stir in chicken and onions.
3. Spray large nonstick skillet with cooking spray and heat on medium-high heat; spoon about 2/3 cup chicken mixture onto half of 1 tortilla; fold in half.
4. Add to skillet, cook 1 minute on each side or until golden brown on both sides.
5. Remove from skillet.
6. Repeat with remaining tortillas and filling.
7. Cut into wedges.