Chop the nuts and toast them in a pan until fragrant. Mash half of the banana with a fork and slice the other half.
Put oats in a pot, add milk and stevia as well as the pinch of salt, vanilla, and cocoa powder. Stir everything together and bring to a simmer on medium heat.
Turn down the heat and let the oatmeal thicken for about 10 to 15 minutes, stirring often.