Is Elsa a muggle

Frozen and Harry Potter are two completely different features and therefore bear no resemblance to each other whatsoever.
Frozen is a animated feature of Disney while Harry Potter is a work of fictional literature.
But to answer your question;
Elsa is simply considered to be a human who happens to be gifted with ice powers and muggles mean humans so Queen Elsa is technically a muggle.

Elsa is a muggle because she has the power to manipulate ice but she can't do spells like expelliarmus.She doesn't even have a wand to use

*shower thoughts*