BACKGROUND: Safe and timely nasogastric tube (NGT) placement is essential for effective enteral nutrition delivery in critically ill patients. Electromagnetic-guided systems has been shown to improve placement accuracy and may reduce delays from confirmatory imaging, but evidence on how nurses acquire competence with this technology remains limited. METHODS: This pre-specified subgroup analysis used data from the nurse-performed electromagnetic-guided arm of a previously published multicenter prospective non-inferiority study conducted across seven ICUs. A total of 23 ICU nurses without prior experience performed 197 tube-placement episodes following simulator training and four supervised cases. Target-range placement was defined as tube tip positioning 3-10 cm below the esophagogastric junction, confirmed by electromagnetic guidance and radiography. Segmented regression was used to explore the learning curve. RESULTS: A potential change point was suggested at Case 2.3 (95% CI: 2.0-2.3), indicating a trend toward early improvement following supervised practice, although this did not reach statistical significance (P = 0.068). Target-range placement rates improved progressively, rising from 57.1% during the supervised phase (Cases 1-4) to 64.6% and 69.2% in the independent-practice phase (Cases 5-7 and 8-15, respectively). Gastric placement was achieved in 99.5% of cases, with no serious complications. CONCLUSION: To our knowledge, this exploratory multicenter study provides the first quantitative characterization of a potential learning curve for nurse-performed electromagnetic-guided NGT placement. Structured training incorporating supervised practice may support early performance improvement and facilitate timely initiation of enteral nutrition in critical care settings.