Hello student yes you can but nlsui will offer firstly to those students who filled it in their first choice and as per their rank it'll be allotted accordingly so if your first choice is NLSIU then you must fill it in first choice and NLASAR in second so even if you score less rank in comparison to NLSUI it won't effect you. You can now even change your prefferd college choices till the last date of CLAT application which is 30th of March by clicking on edit form on official clat constorium website.

Feel free to comment if you have any doubt

Good luck