Your teacher might be looking for the word oxymoron as an additional literary device. The phrases you see in those lines that oppose each other qualify for that device. For example, when we say jumbo shrimp, we are saying big little. These are opposites. She calls Romeo an honourable villain and a damned saint. These phrases do not work together, they are oxymorons.
Another device at work is the rhetorical question that the last line you cited is just beginning. You can't really talk to nature. Juliet is wondering why Romeo would be both her love and her great enemy, but this she did know before she got together with him.
I think that there are at least three literary devices being used here. I do not know which one you would want to identify as the one.
- There are paradoxes. Juliet is saying a number of things that contradict each other. I think that this is meant here to show how torn she is between love for Romeo and hate for what he has done.
- There is hyperbole. She is calling him things like a tyrant and an angel, which he clearly is not. This shows the depth of her emotion.
- Finally, there are metaphors. She is comparing Romeo to all of these things as a way to illustrate what traits she thinks he has.
Allusion: "As Phaethon would whip you to the west" (III.II.3)
Oxymoron: "Beautiful tyrant, angelical fiend" (III.II.75)