In Colombia, best city would be Medellin, as it has a great weather all year round, it's close to cute little towns to visit on weekends, nice people, great internet connection, everything a DN needs.
Pergamino Café is a cozy place with amazing coffee and muffins. The music here is good, Wi-Fi is free and few staff speak in English. You will find many foreigners here.
Medellín is a Digital Nomad’s paradise. Nicknamed the City of Eternal Spring, the weather is perfect all year round. Food is great (I recommend getting la bandeja paisa!) and everything is very cheap as well. I recommend staying around the Provenza area of Poblado which is where all the good restaurants and bars are located. There are a lot of foreigners in this area, but as you’ll see there are a lot of high level entrepreneurs here that are all about building businesses and traveling the world. My favorite coffee shop is called Pergamino. And you have to check out the gym and bar on top of the Charlee hotel!
When taking Uber or a taxi in Medellín, be careful not to slam the car door especially in the taxi. Drivers are very sensitive about this. For new visitors, because of the status of Uber in Colombia, you should always ride in front passenger seat. And EasyTaxi is a popular app to use to request taxis.