In Nigeria, as in other countries, the tech skills that can lead to high income vary depending on the job market and current economic conditions. However, some in-demand tech skills that can be a good investment for someone looking to build a career in the tech industry in Nigeria include:

Web and mobile development: Proficiency in technologies such as HTML, CSS, JavaScript, and various frameworks and libraries is always in high demand.

Data science and analysis: With the increasing availability of data, there is a growing need for people who can analyze and make sense of it. Skills such as machine learning, statistics, and programming languages such as Python and R are in high demand.

Cloud computing: Cloud computing is increasingly being adopted by businesses and organizations, and so professionals with skills in cloud technologies such as Amazon Web Services (AWS) and Microsoft Azure are in high demand.

Cybersecurity: As businesses and organizations rely more on technology, there is a growing need for professionals who can help protect them from cyber threats. Skills such as ethical hacking, network security, and penetration testing are in high demand.

Digital marketing: In an increasingly digital world, businesses need professionals who can help them reach and engage customers online. Skills such as SEO, PPC, and social media marketing are in high demand.

It is worth noting that, regardless of the specific tech skills you choose to develop, it's also important to have strong problem-solving and communication skills, as they are essential in the tech industry.