In saucepan, bring broth to boil; reduce heat to medium-low. Add miso, soy sauce, rice wine vinegar, garlic and ginger; simmer until fragrant, approximately 10 minutes.
Return to boil; cook carrot and mushrooms until tender, approximately 2 or 3 minutes.
Meanwhile, in separate saucepan of boiling water, cook ramen noodles until tender, approximately 1 or 2 minutes (reserve spice packets for another use). Drain and transfer to 4 large soup bowls.
Ladle broth over noodles. Divide carrot and mushrooms among bowls. Top each serving with soft-cooked egg; garnish with green onions and nori.