** British energy firm Centrica CNA.L rises ~2.6% to 167.05p; top pct gainer on FTSE 100 index .FTSE
** Morgan Stanley adds stock to its top-pick list
** Upgrades to "overweight" from "equal weight"; raises PT to 210p from 175p
** Says co gaining strong nuclear momentum, with lifetime extensions to fleet, compelling Sizewell C deal, new advanced modular reactors (AMR) deal with X-Energy in UK
** Trump, during his two-day visit to Britain last week, and UK PM Keir Starmer unveiled nuclear tie-up, including plans by X-Energy and Centrica to build up to 12 AMR in northeast England
** Brokerage believes Centrica well placed, given its strategically important UK gas asset, recent investments into new power generation capacity in UK, Ireland
** Stock rated "buy" on average; median PT is 194.5p, per data compiled by LSEG
** As of last close, CNA up ~25% this year