Nuno's house is comfortable and updated. It's located near historical center. The flat is big - a lot of space for two or 4 people (there are 2 sleeping rooms, 1 kitchen/1 hall). There is good supermarket - around 8 minutes of walking - you can find there good food, cook at home and eat at balcony with nice view of Lisbon =)
PS: Please remember, Lisbon isn't not plateau city - a lot of houses are located at hills - please be ready to go up hills and upstairs - at first time if you have big baggage I highly recommend to take taxi or tuk-tuk to reach home. For usual walking's it's actually okay.