Nidri is a nice, small village where you can find anything you need for a nice little holiday.
I recommend to do the following things while enjoying your Greek surroundings:
Take the Odyssea cruise around the islands
Have a bite at the Barrel or even better: Ta Kalamia. It's a hidden restaurant near the end of the main street. It's not showing the gem inside. It has a couple of tables on the outside, greenish. The menu doesnt show what you're gonna get, but you can choose meat/fish or veggie and you can tell what you don't like. If you're up to haute-cuisine, you will find it over there for a price of your choice.
On the islands you must have a car. We rented a scooter and went by ferries, but if you want to see the whole island, and the inlands, you really need a car.
There's not much history on the island, but the Epirus tour will bring your to wonderful places, like the Acheron river and Parga. In Parga you really should check the castle, it's fantastic, free and huuuge.
Also the waterfalls in Nidri are a really nice refreshment and the walk all the way up there is a nice trip.
Something you really mustn't miss is off course the stunning blue (south)westcoast, which is do-able by scooter, but PLEASE fill up your tank in Vasiliki. Pushing your scooter up the hills isn't funny. Especially not at 40 degrees without shade.
Even in high season boat-rental is possible for everybody with or without license.
If you have the possibility to book your hotel there, you should check out hotel/appartments Iris, all the way to the end of Nidri, but along the coast. The water isn't clear, but it brings very cute turtles and lots of fish and it's really nice, got a pool, clean and quiet.