Heat a large skillet over medium heat. Add olive oil and saute onions for 5 minutes or until soft and translucent. Add ground chicken, salt and pepper and cook until chicken crumbles and is no longer pink (about 5-7 minutes).
While chicken cooks, add cream cheese to a medium-sized bowl and soften in the microwave for about 10-20 seconds.
Add enchilada sauce, ½ cup cheddar cheese, cumin, paprika, and garlic powder to cream cheese and mix until combined. Gently mix in cooked ground chicken.
Line a baking sheet with foil and arrange jalapeños on the sheet, cut side up. Fill each jalapeño half evenly with the enchilada mixture and spread to the edge. Sprinkle evenly with remaining cheddar cheese.
Bake filled jalapeño at 375 degrees F for 18 minutes, then broil on high for 2 minutes until tops start to brown. Serve immediately.