Here's an ideal itinerary for 3 days in Nice with your friends:

Day 1:

• Start your day with a visit to the famous Promenade des Anglais, a beautiful seaside promenade that stretches along the coast of Nice. You can take a leisurely stroll or rent bicycles to explore the area.
• Next, head to the Old Town (Vieux Nice) and wander through its narrow streets and alleys. This charming neighborhood is filled with colorful buildings, quaint shops, and delicious restaurants.
• Stop by the Cours Saleya market, where you can find fresh produce, flowers, and local specialties. It's a great place to grab a quick bite or pick up some souvenirs.
• In the afternoon, visit the Musée Matisse, which houses an impressive collection of works by the famous French artist Henri Matisse.
• End your day with a sunset cocktail at one of the many rooftop bars in the city, such as Le Méridien Nice or La Terrasse du Plaza.

Day 2:

• Start your day with a trip to the Castle Hill (Colline du Château), which offers stunning panoramic views of the city and the Mediterranean Sea. You can hike up the hill or take the elevator for a small fee.
• Afterward, head to the Marc Chagall National Museum, which showcases the works of the famous Russian-French artist.
• For lunch, try some traditional Niçoise cuisine at Chez Pipo, a popular restaurant known for its socca (a chickpea flour pancake).
• In the afternoon, visit the Musée d'Art Moderne et d'Art Contemporain (MAMAC), which features a diverse collection of modern and contemporary art.
• End your day with a night out in the trendy Liberation neighborhood, where you can find plenty of bars and restaurants.

Day 3:

• Start your day with a trip to the nearby town of Antibes, which is known for its beautiful beaches and charming old town. You can take a train or bus from Nice.
• Visit the Musée Picasso, which is housed in the Château Grimaldi and features works by the famous Spanish artist.
• For lunch, try some fresh seafood at Le Bacon, a popular restaurant overlooking the sea.
• In the afternoon, head back to Nice and spend some time relaxing on the beach or exploring the city's many parks and gardens.
• End your day with a farewell dinner at La Petite Maison, a Michelin-starred restaurant that serves delicious Mediterranean cuisine.

I hope this itinerary helps you plan an unforgettable trip to Nice with your friends!