Preheat the oven to 300F (150C).
Stack 3 nori sheets on top of each other and cut them into squares using scissors, a sharp knife, or a pizza cutter. Then cut each square into triangles to resemble nachos.
Using a pastry brush, lightly brush each nori chip with a tiny amount of sesame oil on one side.
Place the chips on a baking tray lined with parchment paper, add the sesame seeds on top. Bake in the middle rack of the oven for 8 to 10 minutes, but keep an eye on them as they can easily burn and get a bitter taste. Remove immediately from the oven and let them cool. Add any additional toppings (chili flakes, extra seaweeds, etc.) and enjoy!
Alternative method: Instead of the oven, you can use a pan to crisp the seaweeds. Add a pan on medium-high heat, add a layer of nori triangles, and let it crisp for 2-3 minutes on each side. Remove from the pan and add your favorite toppings.