She is currently deputy leader of the National Party and in November 2023 was appointed minister of Finance in a coalition government with ACT and New Zealand First.

[10] During the preparation for the 2008 election, practice debate sessions were held for Key with Nicola Willis from his office standing in for Helen Clark.

[25] His replacement Judith Collins[26] left Willis at the same ranking, but with Muller's departure she automatially joined the front bench as 13th in caucus.

[27] With Muller's backers Bishop and Willis rising under Collins, political commentators speculated that "potential dissenters are being kept busy with big new portfolios".

Although she also contested the Wellington Central electorate, voters soundly preferred the incumbent Grant Robertson by more than 3 to 1, with him gaining 27,000 votes compared to her 8,500.

They were elected unopposed on 30 November 2021, after Luxon's main rival, Simon Bridges, dropped his leadership bid in exchange for the finance portfolio.

[43][44] In early August 2023, Willis introduced a private member's bill to allow parents to share their leave entitlement and take time off together.

The plan was criticised by a number of economists during the campaign, with claims there were insufficient wealthy foreigners wanting to buy houses in New Zealand and the Government would be $530 million short each year.

[49] During the 2023 New Zealand general election held on 14 October, Willis unsuccessfully contested the Ōhāriu, which was retained by Labour MP Greg O'Connor by a margin of 1,260 votes.

[52] On 13 December Willis, in her capacity as Finance Minister, declined KiwiRail's request for an additional NZ$1.47 billion to replace its ageing Interislander ferry fleet.

[53] Willis' decision to scrap the project was criticised by Labour's finance spokesperson Grant Robertson,[54] the Maritime Union of New Zealand, the Rail and Maritime Transport Union, the New Zealand Merchant Service Guild and the Aviation and Marine Engineers Association who called on her to resign as Finance Minister.

We have found billions of dollars’ worth of savings within weeks of being elected, and we intend to continue this savings-drive to deliver a better deal for all New Zealanders.” [57] A year later, on 17 December 2024, she conceded that Treasury's finances would remain in deficit until at least 2029.

[59] Following criticism from disabled people's carers and families following the Ministry's cuts which were made without consultation with the sector, Willis summoned Penny Simmonds for an urgent briefing.

[60] On 26 March, she announced that future decisions about the Ministry's funding would go to the New Zealand Cabinet to be signed off, with the disabled community being consulted.

[62] Despite slower than expected economic growth, Willis affirmed the Government's promise to limit the net amount of new money added to the upcoming budget to NZ$3.5 billion.

[66] On 17 December 2024, Willis announced that the minimum wage for adult workers would rise by 1.5% from $23.15 to $23.50; marking the smallest percentage increase since the 1990s.

[67] In November 2024, a group of 15 economists sent an open letter to Nicola Willis and Christopher Luxon criticizing the Government's economic policies as short-sighted, declaring that "your sinking-lid cuts to the public service are powerful contributors to the current severe and prolonged recession."

[68] Less than a month later, Willis projected that the New Zealand Treasury's finances would remain in deficit until at least 2029 due to declining tax revenue and rising expenses.

[70] In addition, Willis confirmed that the Government would adopt a new financial indicator to measure the operating balance before gains and losses (OBEGAL) known as OBEGALx, which excluded ACC deficits from the equation.