Using NVL for multiple columns - Oracle SQL

How about using COALESCE:

COALESCE(ccvl.descr, ccc.char)

You could nest NVL:

 NVL(a, NVL(b, NVL(c, d))

But even better, use the SQL-standard COALESCE, which does take multiple arguments and also works on non-Oracle systems:

COALESCE(a, b, c, d)