Hi bredatascience. Challenge of getting from MVP to full product offering can be approached severe ways, Ive seen. Usually Product defines business requirements.
One way is to define the product vision- where you want to be in a year for example, and then break down each step that will deliver value to users on the way there. Breaking it down is done with tech colleague.
If its more exploratory and bottom up, then define what questions you need answered after launching MVP, and where those answers will lead.

If the question is more about work roles & responsibilities, you can craft a vision for yourself about what you were thinking should happen and how, and then have that conversation with your tech colleague about what s/he was envisioning. If you don't establish shared expectations then it will create a clash when it becomes clear that your expectations were not aligned.