Congratulations on your nomination!
Regarding your question, if you see the checklist:
https://www.canada.ca/content/dam/ircc/migration/ircc/english/pdf/kits/forms/imm5690e.pdf
they only ask for marriage certificate...
Now, in your case.... you will be getting married after your nomination. I've read in other threads that sometimes the official that assesses your application, could thing that you get married only to give the status to the other person. This is very subjective... but if I were you, I would send additional information to demonstrate that your relationship is genuine: bank accounts in common, lease agreements, whatever you have to help convince the official...