Step 1

Turn on a multi-functional pressure cooker (such as Instant Pot®) and select Saute function. Heat olive oil until shimmering, 3 to 5 minutes.

Step 2

Season pork tenderloin with Greek seasoning, salt, and pepper. Add to the preheated pot and cook until browned, about 3 minutes per side. Transfer to a plate. Pour apple juice into the pot; scrape up any pork bits left on the bottom. Set rack inside the pot and place tenderloin on the rack.

Step 3

Close and lock the lid. Select high pressure according to manufacturer's instructions; set timer for 10 minutes. Allow 10 to 15 minutes for pressure to build.

Step 4

Release pressure using the natural-release method for 10 minutes according to manufacturer's instructions. Quick-release any remaining pressure. Unlock and remove the lid. Lift out tenderloin and set aside to rest for 5 minutes.

Step 5

Meanwhile, remove 1/4 cup of the liquid from the pot and mix with cornstarch to make a slurry. Pour slurry back into the pot. Select Saute function and simmer sauce until thickened, about 5 minutes. Slice pork and drizzle sauce on top.