If I play "call to glory" to buff "unsung hero" can I chain sacrifice so the opponent can't stupefy? If the opponent is able to react with stupefy, can I react with sacrifice, so I'm able to draw anyway?

Short answer: No to both main scenarios — the timing of the Mighty check blocks both plays. But there's one narrow path that works if your opponent misplays.

Why "chaining Sacrifice right after Call to Glory" doesn't work:

Call to Glory's "+3 might" is its resolution effect — it doesn't apply until Call to Glory resolves from the chain. If you put Sacrifice on the chain above it (so Sacrifice resolves first), Unsung Hero still has base 2 might when you pay Sacrifice's additional cost. Not Mighty — illegal target for Sacrifice. (Rule 357 — costs paid during step 4, before the spell finalizes.)

Why "letting Call to Glory resolve, then Sacrifice" is risky:

Call to Glory resolves → Unsung Hero is 5 might (Mighty). You then play Sacrifice in the Open State. This would work because Sacrifice's cost kills Unsung Hero instantly (step 4), before the opponent can respond (FAQ #9515, #9906).

However, the opponent has a better option: they can respond to Call to Glory while it's still on the chain with Stupefy. That chain resolves LIFO: Stupefy first (-1 might, 2→1), then Call to Glory (+3 might, 1→4). Unsung Hero ends at 4 might — not Mighty. You can never sacrifice it.

If the opponent Stupefies in response to Call to Glory, can you chain Sacrifice anyway?

No. At that point Unsung Hero has 2 might (Call to Glory hasn't resolved). Still not Mighty. Sacrifice has no legal target for its cost.

The one case where you do draw:

If the opponent plays Stupefy after Call to Glory has already resolved (Unsung Hero at 5), you can respond with Sacrifice — kill the Mighty Unsung Hero as cost, draw 2 + channel 1. Then Stupefy fizzles on the missing target but still draws them 1 card (FAQ #10298, Rule 359.3.e.6). But any smart opponent will Stupefy in response to Call to Glory instead, preventing this.