Set oven to broil. Use the broiler if you want the top of your lasagna to have a crispier texture. You can skip this step if you wish.
Set Instant Pot to SAUTE and add in the 1 tablespoon of oil.
Add diced chicken breasts to the Instant Pot and cook until all sides are no longer pink. Remove from pot.
Add diced onions and minced garlic cloves to the Instant Pot and cook for about 3 minutes. Add in the ¼ cup of flour and the ¾ cup of soy milk. (Regular milk will curdle under pressure.)
Add in the 2 cups of chicken broth.
Add basil, oregano, and black pepper.
Add in 2 cups of Mozzarella cheese and 1 cup of Parmesan cheese. Stir and allow cheese to melt.
Remove from pot and clean the inner liner of the Instant Pot.
In a 7" springform pan, grease all sides with nonstick cooking spray.
Add 2 cups of Mafalda noodles to the bottom of the pan, spreading evenly.
Add half of the cheese sauce you made in the Instant Pot on top of the noodles evenly.
Layer half of the cooked chicken on top of the cheese sauce.
Layer ¾ cups of the ricotta cheese on top of the chicken.
Sprinkle the 1 cup of chopped spinach evenly over the ricotta cheese.
Once again, layer the noodles, cheese sauce, chicken, and ricotta cheese.
Top the rest off with remaining mozzarella and Parmesan cheeses.
Cover springform pan with aluminum foil and set on a sling.
Add 1 cup of water to the Instant Pot and add sling with pan into inner liner.
Close the lid and vent and cook for 20 minutes.
Allow to release pressure for 10 minutes and remove from Instant Pot.
If using the broiler method, remove the aluminum foil from pan and set in the oven for about 3 minutes or until the top of the lasagna starts to brown and bubble.
Unlock the springform pan and lift from lasagna, sprinkle with parsley if desired. Serve.