Your description is a little confusing so I'm going to define the terms. A kitchen island usually means there are cabinets or drawers on one side and a place to sit on the other. Most islands are countertop height which is 36". Most dining tables are no higher than 30".

Standard table height gives better access for children and petite people, so it's a good idea to keep that height for dining. It's also nice to have a lower work space for occasional use. I looked through Houzz's photos for "dining nook island" and could not find where an island was the center of nook seating. Everyone used a table with chairs/bench/built-in seating. That does not mean an island is not possible, but I think you need to make sure seating is easy to get in and out of. It's like one of those big round corner booths in restaurants where half the people might need to get up so a person in the middle could get out. Very inconvenient. Here is an ARTICLE that gives some basic measurement requirements.

So I’m thinking cabinets with an overhang all the way around for seating. And a height of 30 inches. The cabinets and counter will match the kitchen.

post a pic or draw a diagram of your kitchen. there are built in tables into islands if that's what you mean.

@beth very close to you first picture

Not terrible at all but it depends upon the space.

I would need a flor plan and why not just a table and chairs

It would add extra storage and I prefer granite