Do not rely on a single frail Ice-type to sweep him. Instead, use a bulky Water-type that learns Ice Beam (such as Lapras or Vaporeon). They can absorb Lance’s coverage moves and fire back with quad-effective Ice damage.
The Johto Elite Four and Champion Lance feature fully evolved, competitive-grade competitive teams of six, complete with perfect IVs and optimal items (Choice Specs, Life Orbs, Leftovers). The Power of Choice Items and Focus Sashes sacred gold nuzlocke tips high quality
The early game dictates your momentum. Missing key encounters before the second gym can ruin your run before it truly begins. Do not rely on a single frail Ice-type to sweep him