For what it’s worth. Ted Cruz won his Texas Senate seat with 43% of the Hispanic vote.
Whether that percentage can be duplicated in a nationwide presidential race, who knows.
I think Texas Hispanics are generally more conservative than, say, California Hispanics. Cruz might not be able to win 43% nationwide, but I bet he could get several points above that 30% (or less) that's been the best recent Republican presidential candidates could manage.