Place chicken breasts and broth into Instant Pot, sprinkle with seasoning, and mix so that they are well covered with it. Add cream cheese and cheddar, and onions or mushrooms if desired.
Put the lid on and cook on High for 15 minutes with the vent closed. Quick release when completed.
Remove chicken to cutting board or bowl, and shred. Place back into Instant Pot, and combine well.
Add bacon and leek, and serve.