Nanbu Clan

Trade
Unremarkable, furs can be obtained here as well as Otasut - while iron can be sourced from Niputay. These goods make a small profit to the south, though most northern clans seem to have both in abundance. Southern goods can fetch a hefty profit here, but bypass many opportunities to accomplish it. A lacquerware manufactory seems to be profitable, fetching ~160 - but few towns outside of Hirosaki appear to demand it.

Units
VIllager of Tsugaru - The Nanbu can train Elite Skirmishers, these skirmishers are archery specialists rather than firearms, making them better suited to short ranged engagements over elite firearms troops (but, they are still very weak at close-quarters melee).

Ji-Samurai of Tsugaru - The Nanbu can train either Hatamoto Gunners or Hatamoto Cavalry, making their troop-tree quite balanced.

General Starting tips and strategy
The Nanbu Clan is the northernmost clan, and the closest to Hokkaido, the home of the Ezo people. Besides the Ezo (of which something will be said), there isn't anything particulary remarkable about Nanbu Clan territory, save that it can be easily secured against invasion, is proximate to two neutral villages, and borders a wild region (excellent source of slaves and equipment).

On the Ezo:

The Ezo appear as raiding parties and bandit-lairs across Hokkaido, and can be obtained in the neutral villages of Niputay and Otasut (along with iron and furs). The Ezo raiders consist primarily of lightly armored swordmen, with little in the way of ranged troops. Hunting these raiders can be a great source of income (both in terms of loot, and slaves), and provide fair mid-quality equipment; as the Ezo can be looted for quality "native" katanas, nodachi swords, and quite effective light armor (the heaviest are Ezo outfits and nomad boots). When hunting Ezo raider parties, it is highly recommended for the player to engage with ranged weaponry, as the Ezo raiders are really very dangerous at melee combat (due their two-handed swords). The Nanbu Clan is a rather good starting area if you want to join an army, and level your character as a samurai.