Hello Anushka,

If you haven't finished the registration process for NCHM JEE 2019, then you may use different email id to register.  If you are already done with final submission with fee payment, then it is advisable that if it is not very inconvenient then you should use the same email id till counselling as the correction cannot be made at a later stage after submission of an application. 

Hope this answers your query, feel free to ask for more info.