Yes — anyone meeting the eligibility can apply to any regional RRB, regardless of their home state.
There is no domicile requirement for most RRB NTPC posts; your regional RRB is chosen by you at application time.
Apply through the website of the RRB whose posts you want.
Read the official notification carefully — a few posts may have regional or language requirements.
You can apply to only one RRB per notification cycle.