Yes, while it might be tempting to say that the main conflict of The Hunger Games trilogy is character vs. character—Katniss vs. President Snow—but even after Snow's fall from power, Katniss has to continue to fight against societal tyranny. Would-be President Coin would be just as corrupt as former President Snow was. This is why Katniss shoots Coin when she is supposed to shoot Snow.
There is an element of character vs. self in these stories, too. Katniss struggles with who and what to prioritize in her life. Her mother and sister are her top priority, but after that, she struggles with herself—especially during the first games in which she participates: should she pretend to feel more for Peeta than she really does? Or should she allow herself to really feel something for Peeta despite Gale's expectations and the feelings she has for him? Which one should she pick? Gale has been her best friend for many years—he rescues her family when their district is bombed. Peeta, however, understands the way Katniss's mind has been affected by the games; it seems that they both have PTSD and can relate to one another's struggles with their past traumas. Katniss has a hard time pretending, even when it saves her and Peeta's lives, but she has a hard time making real choices as well.