Heat olive oil in a large nonstick skillet over medium-high heat. Add sweet potatoes and ¼ cup maple syrup. Cook for 4 to 5 minutes or until tender, stirring frequently. Cool slightly; transfer to a large bowl. Add chicken strips, cheese, and green onions; toss to combine.

Roll out each refrigerated biscuit to a 4-inch round. Mound chicken mixture in center of 8 biscuit rounds. Place remaining biscuit rounds on top. Pinch edges to seal; fold pinched edges under each biscuit.

Preheat a standard-size waffle iron on medium setting according to manufacturer's directions. Spray top and bottom of waffle grids with nonstick spray. Place 2 filled biscuits in waffle iron, diagonally opposite each other. Close lid, pressing down firmly. Bake 8 to 9 minutes or until filled waffles are golden brown and internal temperature reaches 165°. Remove from waffle iron. Repeat baking remaining filled biscuits. Serve with additional maple syrup, if desired.