Pour 1 cup water into a multi-functional pressure cooker (such as Instant Pot®). Set an elevated trivet inside.
Combine oats, remaining water, coffee creamer, 1/2 teaspoon cinnamon sugar, and salt in a small heat resistant bowl. Set onto the trivet.
Close and lock the lid. Select porridge setting according to manufacturer's instructions; set timer for 5 minutes. Allow 10 to 15 minutes for pressure to build.
Meanwhile, melt butter in a skillet over medium-high heat. Add pecans and sprinkle with cinnamon sugar. Allow butter to brown and nuts to toast, about 1 minute depending on size of pecan pieces. Remove from heat.
Release pressure using the natural-release method according to manufacturer's instructions, about 12 minutes. Release remaining pressure carefully using the quick-release method, about 5 minutes. Unlock and remove the lid. Spoon oatmeal into 2 bowls and top with equal amounts of toasted pecans. Serve immediately.