It looks like a noun because it has a plural-like -S on the end. And there is a noun thanks in English, as seen in the example below:
- Give our thanks to Brenda, when you see her.
However, in the Original Poster's example, thanks is not a noun. It's a preposition. It is one of those prepositions that usually takes another preposition phrase as its complement. The preposition thanks takes a to-complement. Some other examples of similar preposition pairings are:
- due to
- owing to
- because of
- instead of
- away from
In old-fashioned grammar, thanks to, and because of and so forth were described as 'complex prepositions'. Modern grammars, however recognise that these are two independent words. And we can see from the Original Poster's example that this must be correct, because we can very often put other words between them:
- thanks, above all, to its unique language
- owing directly to the new law
Because dictionaries still use nineteenth century grammar analyses, you will still find these described as complex prepositions in dictionaries.
Lastly, notice that many prepositions are converted or 'borrowed' from other parts of speech. Owing, for example comes from the present participle of the verb owe. Due comes from the adjective due. And away and instead derive from noun phrases.