Learn Spanish (Latin America): Ella nunca revisa el cajón.

You don't need no if you put a negative word like nunca (never) directly before the verb. The sentence order here is exactly like English: Ella nunca revisa (She never checks). However, if you want to put nunca after the verb, Spanish requires a "double negative." You would add no before the verb: Ella no revisa nunca el cajón.

Revisa looks like the English word "revise." Is that what it means?

Careful, it's a "false friend"! The verb revisar means "to check," "to inspect," or "to look through." If you want to talk about "revising" your notes for a test, you would use a word like repasar or estudiar.

Is cajón related to the word caja (box)?

Yes! The ending -ón in Spanish often indicates that something is larger or is a specific variation of the root word. While caja means "box," a cajón is a "drawer" (like in a desk or dresser) or a large wooden crate.

Can I drop Ella and just say Nunca revisa el cajón?

Absolutely. Because the verb revisa already tells us the subject is "he," "she," or "you (formal)," you only need Ella if you want to emphasize who is doing it, or to clarify that you mean "she" instead of "he" or "you" if it wasn't already clear from the conversation.