Cool Ranch is likely to be hot at Taco Bell.

The chain is rolling out a new flavor of Doritos Locos Tacos.

Nacho Cheese is big hit for Taco Bell.

The company says it has sold more than 350 million of the tacos.

It was their biggest product launch ever.

The Cool Ranch version will be at Taco Bells March 7, a year after Nacho Cheese was introduced.