To prepare in the instant pot, soak cashews as directed. Add pasta and 4 cups water to instant pot. Lock lid, set valve to sealing, and program for manual-high and 4 minutes. When IP beeps at the end of cook time, quick release, and stir in kale. While pasta is cooking, prepare sauce as directed above. Stir sauce into pasta and kale mixture. Season with additional salt and pepper if desired.