This may be the original building, but there is a question mark. It is the right age and it has the right name, but someone reported that it no longer existed.
1780 Nant, Lleyn. ‘The Methodist cause in Saethon-bach was very small for many years before the chapel was built, namely Capel y Nant. But though in a very low condition, the Head of the church cared for her; and at times the Spirit of God descended in mighty power to ‘trouble the waters,’ so that often one would go from there healed of their affliction. About the year 1780, a very powerful revival broke out in this place, when this moribund cause was wonderfully revived,—it was such a lovely spring after a bare winter. The number of hearers increased, and the number of the disciples, so that they began to say anew, ‘The place is too strait for us: give place to us that we may dwell.’ And they asked in amazement, ‘Who hath brought up these? Behold, we were left alone; these, where have they come from?’ And there was no better answer to give than this, ‘Behold, the Lord God lifted up his hand to the Gentiles, and set up his standard to the people,’ Isaiah 49:20-22.’ [MC ii. 174]The need for a house of worship arose, and in 1782 Capel y Nant was built. [MC ii. 174; see also Goronwy P. Owen, Meth. Llyn ac Eif. p.85-7] Possibly GC Ionawr 1827