In a large sauce pot, heat miso broth, lime juice, garlic, and soy sauce over medium-high until a rolling boil starts. Cook pasta according to package directions - during last 5 minutes of cooking, add broccoli florets. When finished, remove pasta from heat and do not drain.
For tuna, heat olive oil in a skillet over medium-high. Season tuna on both sides with salt and pepper as desired, then add to hot pan and sear for :90 on one side. Flip, and sear for :90 more seconds. Remove from heat.
To assemble, spoon equal amounts of broth, broccoli, and noodles into two large bowls. Add a tuna steak atop or to the side. If desired and available to you, serve with additional soy sauce, teriyaki sauce, and peanuts.