Boil the pasta according to the package instructions, but about 1 minute less than recommended. You want it to be firm because it will be cooked a bit more in the sauce. Reserve at least 1 cup of the boiling water for later use.
Heat the olive oil in a large skillet over medium-low heat. When the oil is hot, add the garlic, pepper flakes, capers. Stir and cook for about 5 minutes until the garlic is very lightly browned.
Add the miso and stir together with the ingredients. Cook for 1 minute.
Add the tomatoes along with the juice in the can. Turn to medium heat Break the tomatoes apart with the spatula. Continue cooking for 10 minutes, stirring often.
Add the pasta, olives, parsley, and spaghetti. Use a pair of tongs to stir well. Continue cooking until the pasta is perfectly al dente, 1-2 minutes. If the mixture becomes dry at any point, gradually add pasta boiling water and stir. The consistency should be saucy but thick enough to eat with a fork.
Taste and season with salt and black pepper as needed. You may not need much salt since the ingredients are already quite salty.
Serve pasta immediately, garnishing with nori and more parsley.