Add basil, pistachios, garlic, olive oil and water to blender or food processor and blend until thoroughly combined. Add Parmesan and blend for 10 more seconds until just combined.
Wait until meatballs are done to finish sauce. Heat chicken stock in large skillet until it comes to a boil. Stir in pesto and goat cheese. Heat over medium-low heat, stirring constantly for 1-2 minutes. Add meatballs and toss to coat. Stir in cherry tomatoes.
Preheat oven to 400°F. Coat a small sauce pan with olive oil over medium heat. Add onion and cook for about 7 minutes or until translucent, stirring frequently. Add garlic and pinch of crushed red pepper and cook for another 2 minutes. Set aside and let cool.
In a large bowl, combine the ground chicken, egg, parmesan cheese, breadcrumbs and basil. Squish the mixture with your hands until mixed. Add the onion mixture and kosher salt and continue mixing with hands. Add the water and mix. The mixture should be fairly wet.
Shape the meatballs to desired size, usually golf ball size. Put some parchment paper on a baking sheet and place meatballs in single layer. Bake for about 20 to 25 minutes or until meatballs start to brown on top. If using right away, add to the pesto sauce to coat. If not using, you can freeze.
Take the time to make your own homemade pesto. You'll notice the difference.
Once you start mixing the meatball ingredients together, do NOT overwork them, otherwise you'll have tough meatballs. You want to mix just until everything comes together.
Speaking of mixing, mix everything with your hands which allows you to incorporate everything without crushing the ingredients.
Place the chicken meatballs on parchment paper before baking so they don't stick.
The meatballs are done when it reaches 165°F internally. You can also slice into one and if there is no pink, it is done.
These meatballs can be stored in an air-tight container for 2-3 days in the fridge or for 3 months in the freezer.