This study aimed to look into the effectiveness of a 6-month health coaching intervention on kidney function in treating patients with type 2 diabetes and early-stage chronic kidney disease (CKD). It was conducted via a two-armed, randomized-controlled trial involving 92 diabetic patients who were regularly followed under the shared care system at a medical center in Taiwan. The intervention group had health coaching and usual care, while the control group had usual care only. During the 6 months, there was a significant improvement in kidney function in those patients who experienced significant worsening of eGFR prior to enrollment. The intervention group significantly improved their eGFR up to 7.92 (SD = 8.32, p = 0.003) and 7.63 mL/min/1.73 m[superscript 2] (SD = 9.71, P < 0.001) within the 3-month and 6-month coaching, respectively, and the control group, neither eGFR nor urinary albumin/creatinine ratio (UACR) changed significantly during the trial. In addition, concurrent use of nutrition supplements at baseline is an essential factor in the effectiveness of intervention in this study. Based on the results of this study, health coaching may help protect kidney function for some patients with type 2 diabetes with early-stage CKD. It should raise awareness and attention to early-stage CKD and public education on the proper use of healthy nutrition supplements. Further studies on this issue with higher-quality evidence and a larger sample size are needed.