Hi, Steven,
Based on a comparison of page numbers in the online index of the earliest marriage records of Southampton Co VA, there doesn't seem to be a page that contains the names of both Nathan Pope and Nancy Stephenson, so they may not have married in that county. However, I did not check for Ann Stephenson, for which Nancy is a nickname. You might want to try that.
I did notice in the online image of the will of Patience Pope, dated 3 Nov 1777 (Southampton Co Will Book 3, p. 264) that she had a son named Nathan Pope. Your Nathan would have been about 6 months old at that time.
There are many references in the various indexes for Nathan Pope. I remember seeing this name when I was doing some of the indexing work myself. It is likely that there are several different men with this name.
Nevertheless, I think it would be worthwhile if you would like to make abstracts of all the wills that make a reference to a Nathan Pope.
Your Nathan Pope's will is in Will Book 13, page 141. One of the witnesses is Henry Pope, a possible relative (brother?).
It might also be helpful to see what other Popes are on the same page as a particular individual. The index can provide this information very quickly. For example, below are the Popes in the index to Will Book 13. There are many Popes on page 141, which indicates that they may be related. In contrast, my Cordy Pope is also in this index, but there is no other Pope on the same page (385), so I am not likely to find any other Pope relatives from the information on that page.
Pope, Amos L., 141
Pope, Anderson, 494, 495
Pope, Augustin, 384, 667
Pope, Augustine, 484, 668
Pope, B. C., 457
Pope, B. E., 143, 320, 321, 332,
340, 351, 406, 457, 490, 544,
548, 555, 561, 673
Pope, Ben B., 464
Pope, Ben E., 272, 313, 425, 426,
493, 494, 545, 663, 681
Pope, Benj E., 58, 74, 249, 257
Pope, Benja E., 154, 468, 527, 558
Pope, Benjamin E., 98, 110, 501
Pope, Bon E., 314
Pope, Cordy, 385
Pope, Dicey, 98
Pope, Eliby, 495
Pope, Elisha, 489, 490, 492, 493,
494, 495
Pope, Elisha F., 141
Pope, Elizabeth, 193, 271, 272, 560,
561
Pope, Giles, 313, 314, 544
Pope, H., 367
Pope, H. P., 249, 268, 293, 313,
332, 340, 351, 406, 449, 458,
490, 539, 540, 548, 555, 561,
581, 587, 619, 620, 673
Pope, Harrison, 355
Pope, Harrison P., 74, 314, 315,
464, 468, 494, 544, 545, 667
Pope, Henry, 141
Pope, Henry T., 154, 155
Pope, Isaac Shepherd, 141
Pope, James, 649, 651
Pope, Jemima Francis, 141
Pope, Jiles, 98
Pope, Jo, 168
Pope, Johnson, 154, 155
Pope, Jordan, 117, 118, 119, 147,
148, 188, 189, 340, 341
Pope, Joseph, 508
Pope, L., 340
Pope, Laurence, 102
Pope, Lawrence, 314, 315, 494, 495,
544, 561
Pope, Lucy, 147
Pope, M. E., 366, 619
Pope, M. R., 154
Pope, Madison, 141
Pope, Martha, 464, 492, 493, 494,
495
Pope, Matthew, 194
Pope, Matthew R., 98, 141, 544
Pope, Mills, 37, 271, 272, 425, 494
Pope, Nancy, 141, 561
Pope, Nathan, 98, 141, 545, 619,
620, 642, 643
Pope, Neverson, 141
Pope, Oswald, 141
Pope, Peter, 642
Pope, Reddick, 141
Pope, S., 406
Pope, Westa, 56, 57, 299
Pope, Wester, 351
Pope, Wilbert, 193
Pope, William B., 545, 643
Pope., 368, 548, 549, 580, 609
I hope this helps.
Charles