Is it haram to call a woman a goddess as a compliment?
Since it does not mean that she literally is a goddess, it is not exactly blasphemy. But it is still not a good thing to say since it borrows pagan imagery, which is not pleasing to God. Rather than thinking of things in terms of halal versus haram only, also think of whether they are pleasing to God or not. The things that are haram are clearly defined and most people know them. But there are many more things that are technically halal but not pleasing to God.
Some can argue it is haram since it contains a pagan meaning. While others will argue it is halal since the intention is not a pagan intention, and the Prophet 
says, “Acts are [to be judged] by their intentions.” (From Sahih al-Bukhari Book 1, Hadith 1; Sahih Muslim, Book 33, Hadith 222)
Don’t say it. Be safe. Allah knows best.
What do you mean by saying it’s not haram? Which scholars have stated that? Referring to a woman as a “goddess” is clearly shirk, and this expression imitates the disbelievers, which is haram.
Abu Hurayrah narrated that the Prophet pbuh said: “A slave (of Allah) may utter a word which pleases Allah without giving it much importance, and because of that Allah will raise him to degrees (of reward). One the contrary, a slave (of Allah) may utter a word (carelessly) which displeases Allah without thinking of its gravity and because of that he will be thrown into Hellfire.” [Al-Bukhari and Muslim]
Allah knows best.