Nope once you have NRN card. You can stay as long as you want and it is valid for 10 years.

Can you get inheritance property with NRN card ? Just wondering.

Online source:
The government has recently launched NRN ID Cards for Nepali people living abroad with foreign citizenship. This comes after the organisation of NRN held a week-long meet in Kathmandu few months ago. The cost of making this ID card is $500 dollars and the benefits which it brings are:
Visa Not Required
Allowed to acquire up to 2 Ropani’s of land in Kathmandu
Allowed to invest in Nepal
Allowed to acquire up to 8 Kattha of land in Tarai Nagarpalika
Allowed to acquire up to 26 ropanis of land in the Pahad region
There are criteria’s to be met ie, which I am still sketchy about. If you want to get your ID card then it is available from the Ministry of Foreign Affairs in Kathmandu or Embassy of Nepal.
They should’ve just implemented the Dual-Citizenship like many other countries, this would’ve made it easier, less-hassle free and it woud’ve saved all the time. Oh Well, im sure the government has their own agenda and so does the NRN. Many Gurkha families in the UK are giving up their Nepali citizenship for the British citizenship available to them for the brighter future it provides. At a crucial time such as this, it wouldve been better to introduce the Dual-Citizenship since many will find it a chore to fork out another $500 for a NRN ID card.

You can purchase 2 ropani land in ktm etc using non card but u need special approval from the secretary of foreign affairs. but it doesnt talk about inherited property. So I guess the old law still holds which means a Nepali with foreign citizenship cant own inherited property. As according to the law at least.