After graduating from the school in 1958, Nelson began a career as a public health nurse in Los Angeles, rising through the ranks to become the clinical nursing director for the North County Health Centers in 1992. She was in that position in 1994 when the region was devastated by the Northridge earthquake. More than 20,000 residents were left homeless, water and electricity were cut off, health centers closed, the Mid-Valley Comprehensive Health Center was severely damaged and Olive View Medical Center curtailed most of its services. Nelson and her nursing staff began operating a triage clinic in their center’s parking lot, and within days had set up tents to give immunizations, triage tuberculosis patients, and provide physical exams for children and prenatal patients. The services proved invaluable, and the nursing staff earned the commendation of then-Secretary of Health, Education and Welfare Donna Shalala.