Solid line = floor (spellings that unambiguously belong to the group). Shaded band up to the dashed edge = ceiling (the most it could reach if every ambiguous spelling counted here).
Nash has been climbing in recent years. All-time it's been given to 22,583 U.S. babies, the 512th most common name by sound today, peaking at 1,607 in 2021, with 1,366 in 2025.
Nash has no common alternate spellings by sound.
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).