Wow this took me forever to figure out! But, here it is.
I guess I had installed the SSL incorrectly on the domain (obviously) the first time.
3. Then under Certificate choose the domain that you wanted to install the SSL certificate on.
4. You will want to click Rekey & Manage
5. You will want to go back and copy the Certificate code that was create in that box and save it.
6. Then follow the instructions here under the title Install an SSL Certificate in Microsoft IIS 10.
7. Login your nopCommerce site as Administrator
8. Click on the Administrator button at the top to take you to the Admin dashboard.
9. On the left menu click Configuration > Stores
10. Then click edit on the store that you want to use.
11. In there you will see the fields in which you will put your company name and all the jazz but you will want to mark the checkbox that says SSL enabled. And you are done-zo!
I have to say that this took me soooooo long to figure but just in case if I forget or someone happens to stumble upon this. I hope that it helped!