Turn Instapot on to saute. Heat the veggie broth and oil and add onion, celery, cauliflower, mushrooms and garlic, saute until almost tender stirring occasionally about 8 minutes. Turn off Instapot. Add veggie broth, rice, seasonings up to/including vegan worcestershire and stir, add pressure cooker lid and cook on high for 22 minutes. Add cashews and nutritional yeast flakes to high speed blender and process till a fine powder. When Instapot is finished cooking let pressure release naturally. Open lid, add cashew/nutritional yeast powder, coconut milk and vegan sour cream stir till well blended. Check seasoning and adjust to taste.