Would nodular melanoma have grown in diameter in 2 years?

Melanoma: Nodular melanoma typically skips the radial growth phase which predominates in the superficial spreading type of melanoma. However, that does not mean that it cannot change in diameter over 2 years. 2 years is way too long time to have a nodular melanoma.

Not necessarily : Just because it doesn't grow in diameter doesn't mean it can't be a nodular melanoma. As stated, these can grow vertically and not radially. If you suspect it is atypical (asymmetric, irregular, color variation, difference) get in for an examination and likely a biopsy.