Heat 1 Tbsp avocado oil in a cast iron skillet over medium heat until shimmering.
Season the chicken thighs evenly with 1 tsp sea salt, 1 1/2 tsp paprika, and 1 1/2 tsp dried oregano.
Place the chicken in the hot skillet skin-side down (if using skin-on) and cook about 7 minutes until browned and crispy; flip and cook another 7 minutes.
Remove the browned chicken to a plate and carefully drain excess fat from the skillet, leaving any fond.
Add 1/2 cup full-fat canned coconut milk, 3 cups baby spinach, 1 cup cherry tomatoes, 1/3 cup drained sun-dried tomatoes, and 1/2 cup chopped fresh basil to the skillet; stir to combine and bring to a gentle boil.
Cook the vegetable and coconut milk mixture 3 to 5 minutes until the spinach wilts and the tomatoes begin to soften.
Return the chicken to the skillet, nestling pieces into the sauce; bring back to a gentle boil, cover with a lid, and cook 35 to 45 minutes until the chicken is cooked through.
Check the chicken for doneness (juices run clear) and adjust seasoning if needed, then serve.
