You can receive a single-entry visa valid for 15/30/90 days at a cost of US$25/40/100 upon arrival at Kathmandu’s Tribhuvan Airport.  The fee is payable preferably in US dollars, but also in major currencies (at land borders officials require payment in US dollars, bring small bills). For use of bank cards, an ATM is available in the airport immigration hall.

Citizens of SAARC countries (Bangladesh, Bhutan, India, Maldives, Pakistan
and Sri Lanka) are not required to pay visa fees for a 30 day visa.

Indian citizens do not require a visa to enter into Nepal.