Nested IF Statement to Populate Field

I'm trying to determine if a proposal is late.  Below is the formula:

If([Proposal Received 2B Alight]<=[PWO Proposal Due Date],"Yes","No")

If(ToDays(Today())<[PWO Proposal Due Date])and If(IsNull[[Proposal Received 2B Alight]) ,"Yes","No")

The first "If" statement works without any issues, but I get the following syntax error on the second "If" statement:

Error:

Column: 0 > There are extra characters beyond the end of the formula.

I'm a new QuickBase user, and any help would be appreciated.