Which figure of speech is used in this text?
I must have eaten too much of Jacob's homemade chili, because now I'm so full I could explode!

 - paradox
 - hyperbole
The text uses hyperbole, an obvious exaggeration that is not meant to be taken literally.
So full I could explode is an exaggeration, since it is clear that the speaker is not actually in danger of exploding.