Hello,

Yes you can apply as you have Indian citizenship. For UPSC, it also allows a candidate from NEPAL also.

you can read the eligibility crteria from the Notice given by UPSC:- https://upsc.gov.in/sites/default/files/Final_Notice_CSPE_2019_N.pdf

In the above pdf you can get it in page number 12.

You can also apply for SSC and railways too. There no barreir but you have to show your documents every where for verification. You will get strictly verified for the nationality identification. so have your documents original and keep them updates as there are some documents which gets expired after some period.

Hope it helps!