Victor says more than once as he recounts his story that he is a victim of fate. For example, he tells Robert Walton, "nothing can alter my destiny." He also says that
Destiny was too potent, and her immutable laws had decreed my utter and terrible destruction.
However, Victor blames "destiny" for his own actions and choices, which were driven by his ambition to become a great scientist and overstep human boundaries by creating life out of inanimate matter. Nobody forced him into this line of research, and, in fact, he does most of his work secretly, isolating himself from others. He also is not destined to have to be on a hunt to destroy the creature: he could have chosen to treat it with kindness and help it rather than reject it. However, Victor's self-concept seems to depend on feeling that he is the victim of some unalterable choice to do all that he freely decided to do.
Environment does not so much impact people as it mirrors their emotional states in the novel. For example, the unhealthy environment in which Victor lives as he drives himself to complete his creature is an indication that he is on the wrong track in life. Further, when Victor and his creature finally have their highly fraught encounter, it happens in the dramatic setting of a cave on a mountain peak in the Alps—a setting that reflects the drama of the moment. Likewise, the frozen and isolated states of both Victor and his creature are mirrored by the frozen Arctic wastelands in which Victor pursues his prey.
However, it must be said that it is environment—nurture, not nature—that turns the creature into a killer. The complete rejection he experiences, especially from his creator, is so painful that he strikes back against it.
Victor, who has overstepped his human role, playing God in a way he was ill-equipped to handle by creating life, has misunderstood this to be his destiny and has gotten out of a healthy relationship with nature. His inability to nurture his "child," the creature, a "natural" thing for a parent to do, has lead to tragedy.