If there is no separation between these components , there is absolutely no way anyone or any software can decide that Achyuta is your first name , Nand is your middle name and Khuntia is your last name.
Anand is a very common Indian name , and your first name can as easily be Achyut.
@achu I suggest you read and re-read @NARAYANK991 post, there is know way of knowing where to split the names, names by their very meaning will be of different lengths so how can Excel know where to start splitting and where to end?
You are asking for a formula to do the impossible, impossible until you post the separation rules but from the way your names are constructed it is still going to be difficult to know where to split the data.