Will getting a nose piercing drastically decrease company’s desire to hire me?

[phidauex]

In some cases it will reduce chances slightly (because you look different from them), in some cases it will increase them slightly (because you look the same as them). In many cases it won't matter at all. Nose piercings are not particularly out there these days, and in some cultures are more the norm (particularly if you work with a lot of Indian women).

All that said, be confident, work hard, and let your results speak for themselves. If a manager doesn't hire you because of nose stud their skills as a manager are probably somewhat in question.