Preheat oven to 400° Fahrenheit and line a baking sheet with parchment paper.
To make the pesto, add the sunflower seeds, nutritional yeast, garlic, artichoke hearts and lemon juice to a food processor. Pulse until combined.
Add the fresh basil and spinach. Stream the olive oil (or avocado oil) in while the food processor runs until the consistency is smooth.
Place chicken thighs on a large sheet pan. Brush or spread pesto on both sides of the chicken thighs. Place in the oven to bake for 30-35 minutes.
While the chicken is baking, prepare the asparagus and tomatoes. If you have room on the sheet pan with the chicken, add them to a bowl, drizzle with oil and sprinkle with Italian seasoning and salt and pepper. You can also just use a separate sheet pan.
When the chicken has 10 minutes left, add the asparagus and tomatoes to the pan with the chicken, spreading them out evenly. Return the pan to the oven to cook for the remaining 10 minutes (or just add in your separate pan with the veggies).
When the chicken is finished, remove everything and serve pesto chicken with the veggies.