Using a steel blade in the bowl of a food processor (or a high-powered blender), add the basil, spinach, walnuts, nutritional yeast, lemon juice, chives, and salt. Blend until evenly ground.
With the machine running, slowly add 1-2 Tbsp of water to the mixture and blend until smooth.
Recipe by Nutrition Twins at https://www.nutritiontwins.com/oil-free-basil-spinach-pesto/