The valley, much of it now screened by undergrowth, was largely a bare geothermal field pocked with mud pools and criss-crossed by rough walking tracks.
Now Te Puia's visitor experience manager, Mr Nicholson sought to treat visitors to sights that had been hidden for years.
Part of a three-year programme, clearing work in often challenging conditions has gained new views of the palisades and Te Puia's waka shelter, while uncovering the mud pools Ngapuna Tokotura and the dormant Papakura Geyser.
The geyser,whose name guide Maggie Papakura adopted and which is situated near the Ngararatuatara cooking pool, had been a major attraction in the valley until it cooled and ceased erupting in 1979, the surrounding vegetation eventually growing over it.
"Simply by clearing away vegetation, we are changing the landscape," Mr Nicholson said.
"It's a simple thing but it is already making a big difference and gradually making the valley once again look as it would have when tourists first started coming here more than 100 years ago."
There are plans to unveil other areas of the valley after this summer's peak visitor season, including plans to re-establish tracks in the southernmost part of the reserve which, after becoming less used, have became overgrown.
The rediscoveries come co-incidentally as new signs of life in the valley's Waikite Geyser have excited geologists.
Once the valley's star geyser, Waikite was capable of spouting steam 20m into the air and a change in geothermal levels had indicated a possible reawakening after 40 years of silence.