Convert Excel Formula to DAX

Try this:

SWITCH(
    TRUE,
    [ARDivisonNo] = "08", "Avertx Billing",
    [Current Product Line] = "SAAS", "SAAS Billing",
    [Current Product Line] = "SUBS", "SAAS Billing",
    [Current Product Line] = "PERP", "Perpetual Billing",
    [Current Product Line] = "BDSW", "Bundled Software Billing",
    TRUE, "Hardware Billing"
)

The SWITCH function will evaluate each condition from top to bottom, stopping when it returns a result of TRUE and returning the matching result. You might have to modify the above to take into account the table names your columns come from.