A person can laugh, that is, audibly express mirth or amusement, in many different ways. On the unrestrained side of the spectrum, one might guffaw, laughing loudly and boisterously. On the more subdued side, one might chuckle. The verb chuckle is defined as “to laugh softly or amusedly, usually with satisfaction.” It is also used to talk about laughing inwardly or to oneself—the way you might when reading (depending on the material!). To chuckle gleefully is to chortle, itself a portmanteau blending the words snort and chuckle.
The adjective powerful can refer to physical strength (a powerful athlete), great effectiveness (a powerful speech), or high potency (a powerful drug). But powerful overlaps with mighty only when describing people or entities that have great power, authority, or influence (a powerful nation). Mighty is chiefly used in a rhetorical manner to indicate uncommon or overwhelming strength or force (a mighty army). Though you might encounter it describing things of uncommon or overwhelming size (a mighty oak; a mighty river), or, things that are great in amount, extent, degree, or importance (a mighty accomplishment).
To confuse someone is to perplex or bewilder them (the flood of questions confused me). To befuddle someone is to confuse them, especially with glib statements or with baffling behavior. The suggestion bundled into befuddle is that of making the mind slow or foggy, as from intoxication, a connotation inherited from the verb fuddle, meaning "to tipple," that is, to drink intoxicating liquor, especially habitually or to some excess. Fuddle entered English nearly 300 years before befuddle, which explains the boozy nature of befuddle's earliest meaning in English: "to make stupidly drunk."