Chop celery and bell pepper into small pieces.
Rinse and drain quinoa.
Dump quinoa into Instant Pot, then bell pepper and celery.
Add 1/4 teaspoon of salt.
Measure 4 well-packed cups of spinach (about half a bag) and dump into Instant Pot.
Pour chicken (or any other) broth into pot.
Close the lid and make sure the vent is set to closed.
Push the manual button, make sure pressure is on HIGH and reduce time to 1 minute.
While the pot comes to pressure and cooks, chop tomatoes and olives.
When the pot beeps several times it has finished cooking. Release pressure in one of two ways: 1) manually release pressure by carefully opening steam valve. Make sure to keep hands clear of steam as it will be hot. This takes a couple of minutes. Or 2) do nothing and allow the pressure to release naturally over about 15 minutes. You will know you can open the pot when the pin to the side of the pressure valve drops.
Add tomatoes, olives, and pesto to the pot. Mix well.
Serve warm or cold topped with feta cheese and almond slivers.