Double-counting courses is permitted in a limited set of circumstances, summarized as follows:

• You can never double-count more than 9 units
• Your B.S. must have more than 180 degree-applicable units for each unit you double-count (so, you need 189 units to double-count 9 units).  This typically limits double-counting to CPE majors and people working on computing related minors
• You can only double-count technical electives, not required courses (CPE 464 can not double-count for CPE majors)
• The course must still meet all the applicable degree requirements

Classes taken as part of the data science minor are not eligible for double-counting, however you may be able to use them as advisor approved electives.  You can find more details here.

This summary leaves out a number of edge cases.  If you doubts or questions talk to the CSSE graduate coordinator.