No you cannot further diploma in IT at a poly to become a degree nurse. This is because in any field when you are building on or furthering the qualifications you hold in order to enter that field the qualification you build on must have a relation to the field. In the case you stated an IT qualification has no relation to the human anatomy with regards to diseases and infectionsin the way nurses deal with them. So to become a degree nurse these are the two ways you can use.
1.You will have to apply with your WASSCE or SSCE results to a place like University of Ghana's Nursing school and do a four year programme.
- You could also use your quaification as a RGN(Registered General Nurse ) to apply to a place like UG, UCC, KNUST,UDS, Presbyterian University etc.
Hope it answers your question fully.