Nyalam is the last larger town before Zhangmu and the bridge across into Nepal, or alternatively the first larger town on the way north to Lhasa. If you are coming up from Kathmandu, beware of the sudden altitude spike and the accompanying dizziness, fatigue and nausea that you might encounter.
The road to and from Nyalam is a rough one; the Nepalese call it the Road to Hell. The altitude stays around 4000 meters and the highway feels like it was paved with basketball sized chunks of stone. Zhangmu at the Sino-Nepali Friendship bridge is 35 km south of Nyalam, Lhasa is 750km north and Kathmandu is 150 km south.
There are some sights to check out in the area, most notably Nyalam Pelgyeling Monastery, built around Milarepa's Cave, about 10 km north of Nyalam, near the village of Zhonggang (Tibetan name). The enlightened yogi Milarepa (1040-1123) and his disciple Rechungpa spent many years in meditation here. The whole complex was rebuilt in 1983 with assistance from Nepalese craftsmen.
The extreme terrain also lends itself well to trekking and hiking (once you get accustomed to the altittude). So if you find yourself in Nyalam for more than a couple days, take the tiome out to hike as far as your lungs can carry you.