First, don't bother with an NDA that is just a waste of time at this point, you are doing pre-sales work here treat it as such. You should walk in as if you didn't know them and were going to a client to talk about this cool new product you built.

In order:

1. State your Agenda to the team

2. Ask them what they hope to learn from the meeting.

3. Do a basic presentation on what the product is and how it can solve the integration problem and the value you can see in the product. Make sure you address anything they specifically mentioned wanting to learn from the meeting (with a couple of exceptions see #4&5).

4. Do a basic demo to show you have something real (MVP is fine) but don't get pulled into design/architecture discussions, just show it works. Talking about the types of technology you used is fine, just stay out of the details or IP side of it.

5. Talk, but do not show anything about roadmapping. Just give specific enough but still vague direction that they know you see the problem and have a plan. They may press for timelines or details depending on their goals, do your best to deflect some of that until you know their intent.

6. Ask lots of follow up questions, see what they think and ask them directly if this is something they can see using and be bold, ask how you get them signed up. That gives you the basis for the next steps.

Assuming they show interest but want more details on the system, then that is where you can go to the next level of engagement and say you'd be happy to share more details once you have a mutual NDA in place. In that NDA you can also protect yourself from them "stealing" the idea and doing it on their own. Technically it just gives you the ability to sue them if they did that, but it generally keeps honest people honest.

Good luck! This is an awesome way to start as a lot of times the prior relationship can be a huge win for both of you. Just be aware you are dealing with them as a potential vendor now so the rules are different.