Bhisan - Hello, my brother works in real estate field, it seems like investing in real estate is like buying gold in terms of security. However, if you are just going to buy it and not utilize it then with the land prices already high in Kathmandu, it won't be such a smart move in terms of return on investment on the short term. You can invest in land maybe outside of the high price area in kathmandu and rent or open like a resort or agro or some other business, since land prices would be relatively cheaper.
If you are really interested, you can PM me and perhaps I can give you more info.