KI Chariot
Lev. 5 Jarl Frostriven
Light Orc Stone Thrower
1 weak Amazon Mancatcher
1 weak Shade

2 Blocking Terrain

Strategy:

I just hide the OST beside blocking terrain (placed at almost the middle of the table) and indirect shoots small figs. The opp. will likely advance due to point loss. The chariot protects OST's rear.

From which country is this national? 300 points constructed?

On your army: I don't think a chariot will stand a change in this AD environment from today...
And besides that, a chariot as a protector of a light OST? Don't think that will make sense.

I think the larger threat is a Bounding MB to take out the shade or the MC. If you can prevent that then it has some options to work with.

Jarl doesn't really lose much at lvl 3, and it saves a decent amount of points that would allow you to fit another attacker. That would be my suggestion.