Add the chicken thighs, kosher salt, black pepper, and olive oil to the Instant Pot. Stir to coat the chicken in the olive oil and seasonings. Add the chopped onion, minced garlic, and chicken broth, stirring to combine.

Seal the Instant Pot and set to cook on high pressure for 10 minutes. Once cooking is complete, let the pressure naturally release to retain moisture and tenderness in the chicken.

Use a slotted spoon to remove the chicken from the Instant Pot onto a cutting board. Shred the chicken with two forks and set aside. Discard the remaining liquid and solids in the pot.

Preheat your oven to 350°F (175°C) to prepare for assembling the casserole.

In a large mixing bowl, whisk together the whipped cream cheese, sour cream, and cottage cheese until smooth. Stir in the condensed cream of chicken soup until well combined.

To the creamy mixture, add shredded cheddar cheese, shredded chicken, kosher salt, black pepper, garlic powder, onion powder, and dried oregano. Mix thoroughly to combine everything evenly.

Transfer the cheesy chicken mixture into a casserole dish, spreading it out evenly.

In a separate bowl, mix the crushed Ritz crackers with the melted unsalted butter until the crackers are thoroughly coated.

Evenly sprinkle the buttery Ritz cracker mixture over the top of the casserole filling.

Place the casserole dish in the preheated oven and bake for 45 minutes until the top is golden and the filling is bubbly.

Remove the casserole from the oven and let it rest for 10 minutes to set. Garnish with finely chopped scallions for a fresh touch before serving.