DDay nails it:

(Just to be clear, the bill has too many tax cuts, and if the Axis of Centrism can't swallow the price tag, they can get rid of the $70 billion AMT patch and the $35 billion home-buying credit and the auto-buying credit, cuts which won't help anyone who can't afford a home or a car and will just give away free money to people who would have bought those items anyway. There's your $100 billion in cuts.)

So if Nelson, Collins et al want to whine about the "cost", they can clip $100 Billion off the price tag by dumping the pointless, wasteful tax custs and credits injected by the wingnuts.  Actually, all the tax cuts woiuld be better replaced by direct spending, since spending has a 1.5:1 effect on GDP and tax cuts only 0.75:1.