Ontario doesn't randomly select your program. Once you are nominated by Ontario you are eligible for a program called "Provincial Nominee Program".
If you open your application on IRCC's portal you'll see a table with title "What am I eligible for?" It looks something like this
Program | Details | Help |
Federal Skilled Worker | Met | ? |
Provincial Nominee Program | Not Met | ? |
Canadian Experience Class | Not Met | ? |
Federal Skilled Trades | Not Met | ? |
This table specifies all the programs for which your are eligible to apply/receive ITA.
So may be what your agent means is that after you get nominated, you'll get additional 600 points but your ITA depends on
1. Current program for which ITAs were issued.
2. Your eligibility to that program.
Since this thread is about Tech Draw I'm assuming that you are already eligible for Federal Skilled Worker, so after getting nominated you can expect ITA for any of the following immigration programs
1. Federal Skilled Worker
2. Provincial Nominee Program
3. No Program Specified