nadar (infinitive (
unconjugated verb)) = (to) swim
nada (3rd-person singular present indicative tense (
conjugated verb)) = he swims, she swims, it swims and you (formal) swim
Look here to see the other conjugations of the verb
nadar.
The noun
nada means 'nothing', but you'll see that it is translated to 'anything' in English, because English doesn't allow a double negative.
No veo nada. = I don't see anything.
The adverb
nada means 'not at all'.
Ella no nada nada. = She doesn't swim at all.