LONGECITY

I have seen in a lot of tortillas they say in the packaging that they contain lime, but this lime is actually calcium hydroxide.  Is this safe to eat?

I'd be more concerned about the tortilla itself.

It's left over from the nixtamalization process that the corn is subjected to.

From wikipedia:

"Maize subjected to the nixtamalization process has several benefits over unprocessed grain: it is more easily ground; its nutritional value is increased; flavor and aroma are improved; and mycotoxins are reduced. Lime and ash are highly alkaline: the alkalinity helps the dissolution of hemicellulose, the major glue-like component of the maize cell walls, and loosens the hulls from the kernels and softens the corn."

It's in the tortillas if that wasn't clear in my post.

Calcium hydroxide is, rarely, used as a calcium supplements or, more commonly, as an added substance in various supplements, because it helps to maintain pH balance within the pills...So, from this, I'd assume it's safe. Everything depends on the amount, though. As a food additive, it is listed as Generally Recognized As Safe (GRAS) by FDA.

Is this corn tortilla's? lime is part of the nixtamal process to dehusk, and consequently  free niacin from corn, not knowing that caused much pellagra when corn was first introduced to the western world

As far as health I doubt the bit in a corn tortilla would compare to the dose you'ld get from a shot of peto-bismo, or which ever one of those uses calcium hydroxide to neutralize stomach acid ....Calcium, Sodium, Potassium, hydroxides are used in different brands because they react with hydrochloric acid to form the corresponding chloride salt, and water...