In the United States, it's fine. It's one of at least four different pronunciations that are common and recognized by US dictionaries. I learned and say "nawsha." Two different US dictionaries, Merriam-Webster and American Heritage, agree in listing all four pronunciations, with the second syllable beginning with "s," "sh," "z", or "zh." Unfortunately they their online websites don't use IPA. https://www.merriam-webster.com/dictionary/nausea nȯ-zē-ə , -sē-ə ; ˈnȯ-zhə , -shə It has audio files. As you see, the way I say it is the least common of the four. A common usage argument involves the word "nauseous." In the US, it is common to say something "makes me nauseous," i.e. makes me feel nausea. Sticklers sometimes say this is incorrect usage. They say that a thing that causes nausea is "nauseous," the person who feels nausea is "nauseated." As a kid, I found even the word "nausea" made me nauseous--I mean nauseated. The first time I read a children's version of Homer's epic poem about Ulysses, I was really bothered by the name "Nausicaa" and really wished Homer had called her by some other name.

Trust a professional dictionary. Collins online dictionary https://www.collinsdictionary.com/dictionary/english/nausea The final syllables are different in "standard" British English. nausea in British (ˈnɔːzɪə , -sɪə) treasure in British (ˈtrɛʒə ) The final syllables are different in "standard" American English also. nausea in American (ˈnɔʃə ; ˈnɔʒə ; ˈnɔsiə ; ˈnɔziə ) treasure in American (ˈtrɛʒər )

/ˈnɔːziə/ /ˈnɔːsiə/ "nausea" /ˈtreʒə(r)/ "treasure" often barely noticeable by many speakers but there is a difference in the ending of each word, therefore in the clear pronunciation. "naus + e-a" and "treas +ur-e" the "u" should be heard at the end "treasure" and there is no "u" to say pronounce or have to hear at the end of the word "nausea" the "u" is in a different location in each word in different syllables of the two words.

Yes , that's perfect.

Sound files at https://www.merriam-webster.com/dictionary/nausea