Melhores lugares para morar em Lisboa para nômades digitais
Good places are the centre of town (Baixa/Marques Pombal) (Although this may be prohibitively expensive), Alcantara (Lots of Startups and a big coworking space at "LX Factory") and Penha de França (Area is getting gentrified, but still relatively cheap).
I'd say to avoid Chelas and any of the areas that are not easily accessible by Metro or the Linha de Cascais. (An exception may be Braço de Prata, between Expo/Parque das Nações and Santa Apolonia, but you'll be a bit isolated there.)
Source: https://www.quora.com/What-are-the-good-areas-to-live-for-a-digital-nomad-in-Lisbon-Portugal-Which-areas-to-avoid