Greek Nī́kē was a goddess before it was a name — the winged figure of victory, of whom the Louvre's Winged Victory of Samothrace is the famous surviving image. The word passed into Christian naming through saints and through compounds like Nicholas, victory of the people, and its feminine forms are still current across Greece and Eastern Europe.
Latin victōria comes from vincere, to conquer, and had a long career as an abstract noun before Queen Victoria made it a mainstream given name in the nineteenth century — a good example of how a single bearer can revive a name that had been dormant for centuries.
The Germanic element sig- is the third major source, seen in the Norse and German names — Sigrid, Sigrun, Sieglinde. It is worth noting how often it compounds with words for beauty, counsel or protection rather than with words for war, which suggests the victory being wished for was not necessarily military.
Arabic naṣr and fatḥ both carry senses of victory, but with a religious inflection: divine help and opening respectively, the second being the word used of the conquest of Mecca. Sanskrit jaya and its compounds run through Indian naming and are frequently attached to deities.
Names in this group are among the few where the wish being expressed is unambiguously competitive, and they are correspondingly rarer for daughters than for sons in most of these traditions — which is itself worth noticing.
The same root, across a whole language family
These are attested shared morphemes — not coincidences of spelling. Where we are not confident a root is shared, we say nothing and simply list the names.