Prior to 1865, cases were reported by private court reporters. There were hundreds of reports series produced under their individual names (e.g. Keen, Barnewall and Adolphus), hence the term "nominate." However, the reports varied greatly in quality. Few law libraries possess a complete collection of these reports even though many of the principles enunciated in these cases continue to be cited today.
For convenience, these nominate reports have been collected and reprinted in three different series:
In Print: Use the Table of Cases in the English Reports, the Revised Reports, the All ER Reprint, or even a more general source like The Digest. For example, if you look up the case name Boutts v Ellis in the Table of Cases to the English Reports, you can find that it is reported in 43 ER 502.
In Print: You can find the various abbreviations of the nominate reports, and in which ER or RR volumes they are reprinted, in Raistrick's Index to Legal Citations and Abbreviations. Justcite has a very helpful chart, and HeinOnline features a Chart of Reports. This list of nominate reports is the central research tool to find reports of nominate cases.
Let's take an example. If you had the citation 4 De G M & G 249, you could look it up in one of these sources. It would tell you that De G M & G stands for De Gex, M'Naghten and Gordon Reports, which reports Chancery cases and consists of 8 volumes from 1851-1857. The volumes of ER (English Reports) or RR (Revised Reports) reprint this series. In this example, volumes 42-44 of the English Reports reprint De G M & G.
Once you located volumes 42 to 44 of the English Reports, you would then need to look at page numbers. The page numbers on the inside top corner correspond to the original pagination of De G M & G. Flip through the pages until you find 4 De G M & G 249. The dark bold face numbers in square brackets interspersed throughout each page correspond to the original De G M & G pagination. Locate  and you have found your case, Boutts v Ellis.
Citation Note: The nominate citation should always be included in the complete citation: Boutts v Ellis (1853), 4 De G M & G 249, 43 ER 502 (Ch).