I would imagine that
Thunder Nyan Nyan would be destroyed. Not, however, because
Elemental Mistress Doriado includes a non-light type(s), but because she does not even include light in her type. I would imagine that since there is no "multi" symbol for attributes, that they just used light, even though that isn't her type.
Aftre all,
Thunder Nyan Nyan's effect says that she is destroyed when there is a non-light monster on the controller's field, not when there is a monster monster with a non-light attribute included in it. Basically,
Elemental Mistress Doriado is a non-light monster, but she is not, for example, a non-earth type, even though elements other than earth are included in her effect.
So if a similar card were to come out that is both, say, light and water,
Thunder Nyan Nyan would not be destroyed, because that monster
is a light monster, it just includes other types as well...
Edit: I only just noticed that
Elemental Mistress Doriado's effect says "also", I didn't notice that, so I would like to reverse my previous opinion, and now say that
Thunder Nyan Nyan would stay on the field even if
Elemental Mistress Doriado was on the field as well.