Season the beef chunks generously with salt and pepper.
Set the Ninja Foodi to 'Sauté' and heat the olive oil. Add the beef in batches, browning on all sides. Remove the browned beef and set aside.
In the same pot, add the onion and garlic, sautéing until softened. Stir in the carrots and celery, cooking for a few minutes more.
Pour in a bit of the beef broth, scraping the bottom of the pot to loosen any browned bits.
Return the beef to the pot along with the potatoes, the rest of the beef broth, tomato paste, Worcestershire sauce, bay leaves, and thyme. Stir well to combine.
Close the Ninja Foodi lid and set it to 'Pressure Cook' on high for 35 minutes. After cooking, allow the pressure to release naturally for 10 minutes, then manually release any remaining pressure.
If you prefer a thicker stew, set the Ninja Foodi to 'Sauté'. Mix the cornstarch and water to create a slurry and stir it into the stew. Allow the stew to simmer until thickened to your liking.
Stir in the frozen peas and let them warm through for about 5 minutes.
Adjust the seasoning with additional salt and pepper if needed. Remove the bay leaves before serving. Enjoy your hearty and flavorful beef stew, perfect for a cozy meal.