Of course you must finish first the Chemical Engineering degree in order to be qualified to work as a Chemical Engineer. Only a plus factor for you is your nanotechnology studies, despite you have not yet completed the course.

Please note that only you can be called Engineer and work as a Chemical Engineer if you have that degree, or else you will only be called laboratory technician if without finishing an engineering degree.

Proceeding to Masters Degree after a Bachelors Degree will be a very good choice to ensure your place to land a better job.

Good luck.

Likely, to obtain a masters in chemical engineering you may have to do certain undergraduate courses in chemical engineering and others (without credit towards the masters) but you would receive undergraduate credit for relevant nanotechnology courses, some of which may be chemical. The actual credit received to enter a masters program may depend upon the university you wish to attend and your grades. You should be welcomed to discuss this with admissions (or your current adviser).

Most chemical engineers like myself go BS in Chem Engr. then specialize in MS. It sounds like you would prefer chemical engineering in the long run so maybe that’s the optimal choice. Most traditional chemical engineering jobs require solid background in fundamental principles of said field. Though anything is possible