I was wondering if Spiked Chain was an exotic weapon the Tian Weapon Training boon could grant proficiency with. It's not explicitly listed on the table mentioned by the boon, but it is listed under Tian weapons that Lantern Lodge PCs can spend prestige points to gain profiency with.
Not sure what's on the list since I don't have the boon, but the Sansetsukon (three-section staff) is an awesome weapon that outshines the spiked chain in almost everyway. 1d10 damage, 19-20 crit range, and replaces trip with blocking. If that's available, use that instead :)
Jiggy
RPG Superstar 2015 Top 32, RPG Superstar 2012 Top 32
But is it finessable? ;)
@The OP: If you're really set on the spiked chain, consider making a half-orc. If you have the APG or ARG, there's an alternate racial trait to make the spiked chain a martial weapon for you instead of "orc" weapons.