Preheat oven to 400 degrees.
Combine chicken, onion, potatoes, chicken stock, peas and carrots, salt, pepper, and poultry seasoning in Instant Pot Multi-Cooker.
Make sure the valve is set to sealing.
Close and lock the lid and select pressure cooker on high pressure. Set the timer for 10 minutes.
Allow pressure cooker to come to full pressure, approximately 10-15 minutes.
While chicken is cooking, unfold the puff pastry. Lightly roll with a rolling pin and then cut to desired size to fit your bowls. I recommend cutting the puffy pastry a bit larger than the bowl as it may shrink.
Place puff pastry on a parchment lined cookie sheet and place in pre-heated oven and bake for 8-10 minutes or until light brown.
When the pressure cooker has completed its cycle allow it to release pressure naturally for an additional 10 minutes and then carefully release any remaining pressure using the valve.
Remove chicken and cut into bite size pieces.
Add butter to the instant pot and select the sauté button.
In a small bowl whisk together milk and flour.
Once stock has begun to simmer, add combined milk and flour and whisk until thickened.
Add diced chicken to the instant pot and heat through.
Serve in small ramekins or bowls topped with puff pastry.