Preheat oven to 400 F.
In a large bowl, toss chicken thighs, olive oil, salt, pepper, paprika, onion powder and garlic powder. Place chicken thighs skin side up in a roasting pan and bake for 45 minutes. Transfer cooked chicken to a platter and set aside. Reserve juices.
Once chicken has been placed in the oven immediately put a large skillet on the stove and add butter. Warm butter over medium heat and add the leeks, sauteing for 4-5 minutes until tender.
Add rice, season to taste and stir. Add wine, sherry, lemon juice and lemon zest, stirring to scrape up browned bits at the bottom of the skillet.
For the next 30-45 minutes, slowly stir risotto with a wooden spoon while adding chicken broth in 1/4 cup intervals every few minutes. The rice will slowly absorb the broth as you stir it. Don't add all of the broth in at once. To release the starch of the rice you need to slowly stir it with broth over time to ensure a creamy texture.
Taste the rice after 30 minutes and if it is al dente add the reserved chicken juices. Stir for an additional 2-3 minutes before pouring the risotto onto a serving platter. Top the rice with chicken thighs (crispy skin-side up) and garnish with fresh thyme, parmesan cheese and lemon wedges. Serve hot.