Final answer:
The nurse should record the assessment in the patient's record.
Step-by-step explanation:
If a nurse notices that a patient's urine is tinged with pink after a cystoscopy, the first action the nurse should implement is to record the assessment in the patient's record. Tinged pink urine can be a normal and expected outcome after a cystoscopy due to the procedure's impact on the urinary tract. However, it is important to document this observation for future reference and to ensure that the patient's condition is carefully monitored.