Correct. The way they pronounce it on the show (car-DE-nas) would be spelled Cardenas. If spelled Cárdenas, it would be pronounced CAR-de-nas.

(The stress is on the penultimate syllable if the word ends in a vowel, n, or s; on the last syllable if it ends in any other consonant; or on the syllable with an accent if the word breaks either of the above two rules.)