Combining two IFs

I need help with building formula within a cell.

There are three fields related to the formula that I am building.

[Close Date] , [Total Days to Close Ticket] , [Aging]

I am building this formula for the [Aging] column.

I have built the two formulas below and they work separately but my challenge is with how to combine these two IFs successfully.

Formula 1) =IF(ISBLANK([Close Date]@row), "NA")

Formula 2) =IF(NOT(ISBLANK([Close Date]@row)), [Total Days to Close Ticket]@row)

My goal is to build a formula where If Close Date field is blank, populate "NA" but, if Close Date Field is not blank, populate the value from the field Total Days to Close Ticket.

I built them separately but not sure how to combine these two.

Thanks in advance.