In 1887 Nimmons was hired by the famous architectural firm of Burnham and Root where he served as a draftsman for 10 years.

Sears, Roebuck and Co. selected them to design their warehouse, distribution and administrative center on West Arthington Avenue at Homan.

It was said to be the largest mercantile establishment in the world at the time and was built in exactly 12 months, an amazing feat of construction.

Nimmons' experience with warehouse design and construction brought him the commission for a large office and storage building for Reid, Murdoch and Co., built between 1912 and 1913 along the north bank of the Chicago River between Clark and LaSalle.

Nimmons' numerous articles in leading architectural magazines expounded on his concept of industrial design and its impact on employees.