If you become a US citizen, legally you are not allowed to acquire parental property. With NRN ID card, we can acquire certain amount of property according to the location as someone posted above, but only with the money you have earned abroad or in your case, in US. You have to show the proof of income for that. If you, anyway, acquire parental property but one of your siblings go ahead and report that you are not a Nepali citizen anymore, then you will be stripped of that property. If you want to be on safe side in terms of the parental property and want to get US citizenship as well, then you should first clear all the settlements of the property with your parents/siblings, sell all those and then become  US citizen. Otherwise, you have to take a risk. If you dont have any such threats from your parents/siblings, you can still keep them with your nepali nagarikta as long as nobody bothers to report. Another thing after you become a citizen here, you will be liable to pay taxes to US govt. on the income and assets you have in Nepal or any other country. So, you weigh your pros and cons and make a decision.