Nichols Institute reported that net income for the year ended Dec. 31 rose to $1.4 million, contrasted with a loss the year before of $108,000. Revenues increased 58% to $55.2 million from $34.9 million. The company said the 1986 figures were affected by expansion costs. For the fourth quarter, net income was $463,000, up from the $101,000 posted a year ago. Revenues rose 50% to $14.3 million from $9.5 million. Nichols Institute, based in San Juan Capistrano, operates clinical laboratories and specializes in providing diagnostic medical testing services. It also manufactures medical diagnostic test kits and performs research and development.