Identifying nested/overlapping reading frames in nucleotide sequences
An RNA sequence has six possible reading frames depending on the offset (0, 1, 2) and the direction (forward, reverse complement). All frames can potentially be used for  protein translation, but only one frame per protein (i.e. there is no shifting going on when translation is happening, excluding shifts introduced by splicing).
If you need to find all the possible protein sequences within an RNA sequence, there are plenty of programs already available (e.g. getorf and transseq from the EMBOSS tool kit).